Abrasive cleaners have long been utilized as a household product. These compositions possess a physical "cutting" action that is most advantageous in removing stubborn stains and dirt deposits from fixtures, floors, appliances, etc. Almost universally, however, such cleanser compositions are marketed in the dry, powdered form. In such form, the compositions are somewhat difficult to apply to some surfaces, especially vertical surfaces; and, in addition, tend to cake and lump if accidentally moistened, thus interfering with the pouring and application thereof. Further, such cleansers most usually employ abrasives of a relatively high hardness, whereby their cleansing action is quite severe. They find their greatest use, therefore, in the most difficult cleansing situations.
On the other hand, there are large numbers of cleaning compositions, usually liquids, detergent and surfactant based, that are useful in normal light or easy soil removing operations. These compositions lack an abrasive component and are therefore relatively poor in removing stains and tightly adhering particles or dirt. Such compositions fall into the "light duty" category of cleaning compositions.
It is clear that both aforementioned types of cleaners suffer deficiencies, i.e., difficulty of application to some surfaces and harsh action in the case of abrasive cleaners, and "light duty" cleaning efficiency in the cases of liquid detergents.
It is therefore apparent that a liquid abrasive detergent composition would provide a useful intermediate range of cleaning compositions. Such a composition should provide relative ease of application, but yet have strong cleanser properties akin to those of the abrasive cleanser category.
There have been some prior attempts to produce such liquid abrasive compositions. But the principal road block to success is the difficult problem of achieving a stable suspension of the abrasive in the liquid medium. Since abrasive materials must not dissolve in the suspension medium in order to retain their "cutting action", they remain in the particulate state; at the same time, these abrasive particles are universally heavier, on a mass per unit volume basis, than the liquid suspension medium, whereby the particles tend to settle to the bottom of the container unless the suspending force of the medium is greater than the gravitational force on the particles. Attempts have been made to achieve liquid or pourable abrasive suspensions with suitable detergent capabilities; some success has been noted in the literature, for instance, U.S. Pat. No. 3,281,367. Other prior patents, such as U.S. Pat. Nos. 3,149,078; 3,210,285; 3,210,286; 3,214,380; 3,522,186; 3,630,922; and 3,677,954 deal with detergent compositions or components therefor having general applicability to the present invention. The publication in "Soap and Sanitary Chemicals", February 1951, page 41 by Sanders and Knaggs discusses "High Viscosity Detergent Solutions" of further interest in the present invention.
However, despite the referred to previous works, a fully stable liquid abrasive detergent composition appears to have eluded prior workers.